In the related art, a drug solution is administered to a patient by an injection syringe, and then the injection needle is recapped with a protector before being discarded. However, so-called puncture by mistake such that medical workers such as nurses pick their own finger with an injection needle having patient's blood attached thereon by mistake at the time of recapping, or the recapping protector is separated from the needle for some reason and workers who handle the injection needle pick themselves with the used injection needle has been a problem. Through such puncture by mistake, the medical worker may be infected with bacteria or virus existing on the injection needle, whereby the medical worker may be affected by a disease.
In order to avoid the problem of puncture by mistake as described above, tools which are capable of safely disposing used injection needles without touching the used injection needles, for example, a needle discard container as shown in Patent Document 1, have been proposed, and there are medical institutions which employ this discard container.
However, in the case where emergency medical procedures are required for a patient such as in critical care centers, or in places where the discard container can hardly be installed, it is impossible to discard the injection needles using the discard container.
Therefore, there is proposed a structure of an injection syringe which allows the injection needle to be discarded safely without puncture by mistake. For example, there is an injection syringe provided with a tube outside an injection barrel. The tube is capable of engaging the distal end of the injection barrel and of sliding toward the distal end of the injection barrel, and has an inner diameter which is substantially equivalent to the outer diameter of the injection barrel. This injection syringe is capable of avoiding a puncture by sliding the tube toward the distal end of the injection barrel and covering the portion from the distal end of the injection barrel to beyond the distal end of the needle with the tube after use (Patent Document 2).
There is also an injection syringe configured to be capable of storing the needle in the injection barrel. After a patient is administered medicine, a plunger is connected with the needle by pushing the plunger into the distal end of an injection barrel, so that the plunger and the needle are operable. The needle is retracted into the injection barrel by pulling the plunger, and then the needle is completely stored in the injection barrel in an inoperable state by separating the plunger, thereby being discarded safely (Patent Document 3).
Patent Document 1: JP-A-1-242064
Patent Document 2: JP-A-5-337182
Patent Document 3: JP-A-2003-205035